1. Field of the Invention
The invention relates to a key mechanism, and more particularly to a key mechanism preventing a linking bar from separating from a base plate.
2. Description of the Related Art
Generally, in a key mechanism, a linking bar is disposed between a base plate and a keycap to enable uniform function of the keycap.
Referring to FIG. 1A and FIG. 1B, a conventional key mechanism 1 comprises a base plate 11, a keycap 12, and a linking bar 13. In FIG. 1A and FIG. 1B, depiction of a scissors linking device, an elastic dome, and a membrane circuit assembly is omitted to simplify the diagrams. A plurality of pivoting portions 11a is disposed on base plate 11. A plurality of engaging portions 12a is disposed on keycap 12. The linking bar 13 comprises a main body 13a and two free ends 13b. The main body 13a is rotatably engaged in the engaging portions 12a of the keycap 12 while the free ends 13b respectively pivot to the pivoting portions 11a of the base plate 11. When the keycap 12 is pressed, the main body 13a of the linking bar 13 moves with the keycap 12 and the free ends 13b thereof rotate in the pivoting portions 11a. 
When the keycap 12 is removed or separated from the base plate 11 due to collision, the linking bar 13 is also often separated from base plate 11 (or separated from the pivoting portions 11a) following the keycap 12. Accordingly, as the linking bar 13 must be assembled on the keycap 12 and base plate 11 using a specific means, re-assembly of the linking bar 13, keycap 12, and base plate 11 is inconvenient.